How to stash all actions to current armature?
This does it, but i can't actually unregister the addon.

It needs to be run from the space menu with the cursor in the dopesheet in action mode.

bl_info = {
    "name" : "stash all",
     "catagory" : "Action",
}

import bpy

class StashAll(bpy.types.Operator):
    """My Stashing Script"""
    bl_idname = "action.stash_all"
    bl_label = "stash all"
    bl_options = {'REGISTER'}

    def execute(self, context):
        ob = bpy.context.object

        if ob.animation_data is None:
            ob.animation_data_create()

        ad = ob.animation_data

        for action in bpy.data.actions:
            ad.action = action
            track = ad.nla_tracks.new();
            track.strips.new(action.name, action.frame_range[0], action)

        ad.action = null

        return {'FINISHED'}

def register():
    bpy.utils.register_class(StashAll)

def unregister():
    bpy.utils.unregister_class(StashAll)

if __name__ == "__main__":
    register()